Self-ligating orthodontic bracket

ABSTRACT

An orthodontic bracket having a bracket body configured to be mounted to a tooth includes an archwire slot having a base surface defining a base plane and a slide engagement track defining a translation plane. The translation plane is angled with respect to the base plane. A ligating slide is engaged with the slide engagement track of the bracket body and movable along the slide engagement track and parallel to the translation plane between an opened position, in which an archwire is insertable into the archwire slot, and a closed position, in which the archwire is retained within the archwire slot. The translation plane is angled with respect to the base plane so as to prevent the ligating slide from contacting the gingiva surrounding the tooth when the ligating slide is moved to the opened position.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/996,648 filed Jan. 15, 2016, which is a continuation of U.S.application Ser. No. 13/792,097 filed Mar. 10, 2013, which is acontinuation of U.S. application Ser. No. 13/052,759 filed Mar. 21, 2011(now U.S. Pat. No. 8,393,896), which is a continuation of U.S.application Ser. No. 11/837,169 filed Aug. 10, 2007 (now U.S. Pat. No.7,909,603), which is a continuation of U.S. application Ser. No.11/032,977 filed Jan. 11, 2005 (now U.S. Pat. No. 7,267,545), thedisclosures of which are incorporated by reference herein in theirentireties.

FIELD OF THE INVENTION

The invention relates generally to orthodontic brackets and, moreparticularly, to self-ligating orthodontic brackets.

BACKGROUND OF THE INVENTION

Orthodontic brackets represent a principal component of all correctiveorthodontic treatments devoted to improving a patient's occlusion. Inconventional orthodontic treatments, an orthodontist or an assistantaffixes brackets to the patient's teeth and engages an archwire into aslot of each bracket. The archwire applies corrective forces that coercethe teeth to move into correct positions. Traditional ligatures, such assmall elastomeric O-rings or fine metal wires, are employed to retainthe archwire within each bracket slot. Due to difficulties encounteredin applying an individual ligature to each bracket, self-ligatingorthodontic brackets have been developed that eliminate the need forligatures by relying on a movable portion or member, such as a latch orslide, for captivating the archwire within the bracket slot.

Conventional orthodontic brackets for the first and second molar teethtypically include a bracket in the form of a buccal tube that providesan anchor for the archwire. The buccal tube is typically secured to atooth or to a molar band, which is in turn cemented to the first orsecond molar teeth. A terminal end of a conventional archwire is thenfitted into the tube to facilitate orthodontic treatment. In someorthodontic treatments, a severely rotated molar makes it difficult toinsert the end of the archwire into both the first and second molartubes. In these severely rotated cases, a convertible buccal tube isoften used on the first molar tooth to overcome the difficultyencountered with conventional buccal tubes.

In some orthodontic treatments, however, it is undesirable to fix thearchwire and prevent movement of the archwire, as is done whentraditional ligatures secure the archwire to a convertible buccal tube.To overcome this limitation of current molar brackets, it would bedesirable to use self-ligating brackets on the first and/or secondmolars. Nevertheless, their use has heretofore presented someundesirable drawbacks. For instance, one problem in using self-ligatingbrackets on the molar teeth is that their size often creates occlusionproblems between the bracket and teeth on the opposing jaw. As the upperand lower teeth are brought together, such as for example, duringchewing, the upper teeth may contact the brackets on the lower molarsand may break or dislodge the brackets therefrom.

Furthermore, under normal conditions the gingival-occlusal height ofmolar teeth provides a limited surface on which to mount an orthodonticbracket. Prior self-ligating brackets have slides that engage thebracket body from below and travel along guides in the bracket body thatare substantially parallel to the gingival-occlusal plane. Moreover,when in an opened position, the bottom edge of the slide extends belowthe bracket body. Thus, if traditional self-ligating brackets wereattached to the bottom molar teeth, the bottom edge of the slide wouldcontact gum tissue (gingival) causing patient discomfort. Moreover,because gingival interference with the slide would be significant, theslide could not be fully opened to accept an archwire thus defeating anadvantage of self-ligating brackets.

Yet another problem often encountered with traditional direct bondedself-ligating brackets is with applying the brackets to teeth. To applya self-ligating bracket to a tooth, a medical practitioner will use atool, such as tweezers, to grasp the bracket and manipulate the bracketwithin the oral cavity. Traditional self-ligating brackets, however,typically do not provide convenient gripping points so that the medicalpractitioner may securely grasp the bracket. Consequently, it isdifficult to manipulate the bracket within the oral cavity without thebracket disengaging from the tweezers and falling on the floor or in apatient's mouth. This problem would be exacerbated when attempting toapply self-ligating brackets to molar teeth at the rear of the oralcavity.

There is a need for a self-ligating orthodontic bracket attachable tomolar teeth that overcomes these and other deficiencies of conventionalself-ligating orthodontic brackets.

SUMMARY OF THE INVENTION

In one aspect of the invention, an orthodontic bracket includes abracket body configured to be mounted to a tooth and includes anarchwire slot having a base surface generally defining a base plane. Thebracket body further includes a slide engagement track generallydefining a translation plane. The translation plane is acutely angledwith respect to the base plane. A ligating slide is engaged with theslide engagement track of the bracket body and movable along the slideengagement track and parallel to the translation plane between an openedposition, in which an archwire is insertable into the archwire slot, anda closed position, in which the archwire is retained within the archwireslot. The translation plane may be angled between approximately 10degrees and approximately 25 degrees, and preferably approximately 20degrees, with respect to the base plane. The angled relation between thetranslation plane and the base plane is configured to prevent theligating slide from contacting the gingiva surrounding the tooth whenthe ligating slide is moved to the opened position.

To provide a close fit between the archwire and the archwire slot, theligating slide includes a surface confronting the slide engagement trackhaving a first and second portion. The first portion engages the slideengagement track. The second portion covers the archwire slot when theligating slide is in the closed position and is angled with respect tothe first portion so that the second portion is generally parallel tothe base plane.

In another aspect of the invention, the bracket body includes aconfronting side adapted to face teeth on an opposite jaw. Theconfronting side has a contoured shape such that as the jaws are closedand the upper and lower teeth are brought together, there is no occlusalinterference between the orthodontic bracket and the teeth in theopposite jaw. The confronting side may include a recess adjacent anouter end that defines a generally planar surface which is substantiallyorthogonal to the base plane. The planar surface is adapted to provide agripping point for an orthodontic tool, such as tweezers, used to applythe bracket to the tooth.

In yet another aspect of the invention, the movement of the ligatingslide relative to the bracket body may be restricted so as to preventthe ligating slide from disengaging the bracket body. The bracket bodymay include one of a projecting portion or a receiving portion and theligating slide may include the other of the projecting portion and thereceiving portion, wherein the projecting portion or receiving portionmoves relative to the other as the ligating slide moves along the slideengagement track between the opened and closed positions. The receivingportion includes a first end configured such that the projecting portionengages the first end when the ligating slide is in the opened position.In this way, the ligating slide is prevented from accidently orinadvertently disengaging from the bracket body.

In one embodiment, a retaining pin projects from the slide engagementtrack and the ligating slide includes a retaining slot extending throughthe ligating slide and oriented in a direction along which the ligatingslide moves between the opened and closed positions. The retaining pinis received within the retaining slot and the retaining slot movesrelative to the retaining pin as the ligating slide moves between theopened and closed positions. Another embodiment further shows theretaining pin associated with the ligating slide and a retaining grooveassociated with the bracket body that operates in a similar manner asdescribed above. Other configurations are also possible for restrictingthe movement of the ligating slide relative to the bracket body. Forinstance, in other embodiments of the invention, the slide engagementtrack is bounded by at least one side wall having one of a projectingportion or a receiving portion and the ligating slide includes aperipheral edge that confronts the side wall. The peripheral edgeincludes the other of the projecting portion or the receiving portion.The projecting portion may be, for example, a retaining pin or aretaining ball and the receiving portion may be a retaining groove.

The above and other objects and advantages of the invention shall bemade apparent from the accompanying drawings and the descriptionthereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of the invention and,together with a general description of the invention given above, andthe detailed description of the embodiments given below, serve toexplain the principles of the invention.

FIG. 1 is a perspective view of a self-ligating orthodontic bracketaccording to the invention in which the ligating slide is removed fromthe assembly for clarity;

FIG. 2 is a perspective view of the self-ligating orthodontic bracket ofFIG. 1 with the ligating slide in the closed position;

FIG. 3 is a cross-sectional view of the self-ligating orthodonticbracket of FIG. 2 generally taken along line 3-3;

FIG. 4A is a cross-sectional view of the self-ligating orthodonticbracket of FIG. 2 generally taken along line 4A-4A showing a retainingpin in the bracket body and a retaining slot through the ligating slide;

FIG. 4B is a cross-sectional view of an alternate embodiment of theself-ligating orthodontic bracket similar to FIG. 4A showing a retaininggroove in the bracket body and a retaining pin in the ligating slide;

FIG. 5A is a perspective view of an alternate embodiment of theself-ligating orthodontic bracket showing a retaining ball in thebracket body and a retaining groove in the ligating slide; and

FIG. 5B is a broken away perspective view of an alternate embodiment ofthe self-ligating orthodontic bracket similar to FIG. 5A showing aretaining groove in the bracket body and a retaining pin in the ligatingslide.

DETAILED DESCRIPTION

Although the invention will be described next in connection with certainembodiments, the invention is not limited to practice in any onespecific type of self-ligating orthodontic bracket. The description ofthe embodiments of the invention is intended to cover all alternatives,modifications, and equivalent arrangements as may be included within thespirit and scope of the invention as defined by the appended claims. Inparticular, those skilled in the art will recognize that the componentsof the embodiments of the invention described therein could be arrangedin multiple different ways.

With reference to FIGS. 1 and 2, an orthodontic bracket, generallyindicated by reference numeral 10, includes a bracket body 12 and amovable ligating slide 14 slidably coupled with the bracket body 12. Thebracket body 12 includes an archwire slot 16 formed therein adapted toreceive an archwire 18 (shown in phantom). The ligating slide 14 ismoveable between an opened position in which the archwire 18 isinsertable into the archwire slot 16 and a closed position in which thearchwire 18 is retained within the archwire slot 16. The bracket body 12and ligating slide 14 collectively form an orthodontic bracket 10structure for use in corrective orthodontic treatments. The invention isadvantageous for self-ligating brackets placed on the first and/orsecond molar teeth, although not so limited.

More particularly, the invention is advantageous for self-ligatingbrackets placed on the first and/or second molar teeth of the lower jaw.For this reason, the orthodontic bracket 10 of the invention isdescribed herein using a reference frame attached to a molar tooth ofthe lower jaw. Consequently, and as used herein, terms such as labial,lingual, mesial, distal, occlusal, and gingival used to describe bracket10 are relative to the chosen reference frame. The invention, however,is not limited to the chosen reference frame and descriptive terms, asthe orthodontic bracket 10 of the invention may be used on other teethand in other orientations within the oral cavity. By way of example, theorthodontic bracket 10 may be used on the molar teeth in the upper jawand oriented so that the ligating slide 14 opens in either the occlusalor gingival direction. Those of ordinary skill in the art will recognizethat the descriptive terms used herein may not directly apply when thereis a change in reference frame. Nevertheless, the invention is intendedto be independent of location and orientation within the oral cavity andthe relative terms used to describe orthodontic bracket 10 are to merelyprovide an adequate description of the invention. As such, the relativeterms labial, lingual, mesial, distal, occlusal, and gingival are in noway limiting the invention to a particular location or orientation.

The bracket body 12 has a lingual side 20, an occlusal side 22 whenmounted to a tooth 23 carried by the patient's lower jaw, a gingivalside 24, a mesial side 26, a distal side 28, and a labial side 30. Thelingual side 20 of the bracket body 12 is configured to be secured totooth 23 in any conventional manner, for example, by an appropriateorthodontic cement or adhesive or by a band around an adjacent tooth.The lingual side 20 may further be provided with a pad 32 that issecured to the outer surface of tooth 23.

In one advantageous aspect of the invention, the occlusal side 22 isprofiled or contoured by including a labial portion 34 that projectsgenerally in the gingival-labial direction. For instance, the occlusalside 22 may include a convex portion adjacent the lingual side 20 with aconcave portion extending therefrom in the labial direction. In thisway, the thickness of the bracket body 12 between the archwire slot 16and occlusal side 22 is relatively thicker along the convex portion andthins or is reduced along the concave portion. Many traditionalself-ligating brackets have an occlusal side that projects primarily inthe labial direction. Consequently, when traditional self-ligatingbrackets are positioned on molar teeth, teeth on the opposing jaw oftencontact the occlusal side of the brackets when the teeth are broughttogether, such as for example during chewing. To avoid the undesirablecontact of teeth with the orthodontic bracket, the self-ligating bracket10 of the invention includes an occlusal side 22 with a labial portion34 that projects in the gingival direction as well. This profiling movesthe occlusal side 22 away from the teeth on the opposing jaw, shownschematically at 35, so that as the teeth 23, 35 are brought together,the teeth 35 on the opposing jaw do not contact the occlusal side 22 ofthe orthodontic bracket 10, thereby preventing occlusal interference(FIG. 3).

Occlusal side 22 may further include recess 36 in labial portion 34.Recess 36 may be advantageously configured to include a generally planarsurface 38 adapted to be a gripping point for a tool (not shown), suchas tweezers, for manipulating the orthodontic bracket 120 within theoral cavity. As discussed below, planar surface 38 is generallyorthogonal to the base plane defined by the base of the archwire slot16. This is particularly advantageous when attaching orthodonticbrackets to molar teeth at the back of the oral cavity, where it can bedifficult to manipulate the bracket 10 so as to properly attach thebracket 10 to the molar teeth 23. Many traditional self-ligatingbrackets include occlusal sides that are irregular and thus are notconducive to gripping by an instrument such as tweezers. To aid themedical practitioner in applying the self-ligating bracket 10 of theinvention, planar surface 38 is provided within recessed area 36. Planarsurface 38 provides an enhanced surface for securely gripping theorthodontic bracket 10 so that the medical practitioner may easilyposition the bracket 10 on the molar tooth 23.

With continued reference to FIGS. 1 and 2, the bracket body 12 includesa base surface 40 and a pair of opposed slot surfaces 42, 44,respectively, projecting labially from the base surface 40 thatcollectively define the archwire slot 16 extending in a mesial/distaldirection from mesial side 26 to distal side 28. The slot surfaces 42,44 and base surface 40 are substantially encapsulated or embedded withinthe material of the bracket body 12. The archwire slot 16 of the bracketbody 12 is designed to receive the orthodontic archwire 18 in the samemanner as typical prior art self-ligating orthodontic brackets.

The bracket body 12 further includes a generally planar support surface46 projecting in a generally labial-gingival direction from slot surface44. Support surface 46 may include a pair of slide grooves 48, 50extending in the occlusal-gingival direction at opposed mesial-distalends of support surface 46. A pair of opposed guides 52, 54 are carriedby support surface 46 and are positioned on respective mesial and distalsides 26, 28 thereof. The guides 52, 54 are generally L-shaped eachhaving a first leg projecting from support surface 46 in the labialdirection. Guide 52 has a second leg projecting in the distal directionwhile guide 54 has a second leg projecting in the mesial direction sothat collectively, guides 52, 54 partially overlie support surface 46.Planar support surface 46 including grooves 48, 50 and guides 52, 54collectively define a slide engagement track 56 for supporting andguiding ligating slide 14 within bracket body 12.

In another advantageous aspect of the invention, the slide engagementtrack 56 and the archwire slot 16 generally have a non-orthogonalrelationship. In particular, the base surface 40 of the archwire 16generally defines a base plane 58 and the slide engagement track 56generally defines a translation plane 60 along which the ligating slide14 moves between the opened and closed positions. It should berecognized that base surface 40 and slide engagement track 56 need notbe precisely planar but be configured such that base plane 58 andtranslation plane 60 may be generally defined. The base plane 58 andtranslation plane 60 are acutely angled with respect to each other by anangle A, as shown in FIG. 3. In this way, as the ligating slide 14 ismoved from the closed position to the opened position along slideengagement track 56 and parallel to translation plane 60, the ligatingslide 14 moves generally in the labial-gingival direction so that theedge of the ligating slide 14 does not make contact with the gingiva 61adjacent orthodontic bracket 10 when mounted to molar teeth 23. Toprevent the ligating slide 14 from contacting the gingiva 61, the baseplane 58 and translation plane 60 have an angle A between approximately10 degrees and approximately 25 degrees, and preferably approximately 20degrees. The invention, however, is not so limited and, as recognized bythose of ordinary skill in the art, other angles suitable for aparticular application are possible.

The ligating slide 14 is a generally planar structure comprising amesial portion 64, a distal portion 66, and a central portion 68intermediate the mesial portion 64 and the distal portion 66. Mesial anddistal portions 64 and 66 include integral slide rails 70, 72 extendingin the occlusal-gingival direction and adapted to engage slide grooves48, 50 of bracket body 12 when ligating slide 14 is engaged with bracketbody 12. Additionally, guides 52, 54 overlie mesial and distal portions64, 66 respectively, and central portion 68 projects in the labialdirection such that the labial surface of central portion 68 issubstantially flush with the labial side 30 of bracket body 12. Thelabial surface of central portion 68 may include a channel 74 thattapers or narrows in the occlusal-gingiva direction and includes anaperture 76 located near the apex of channel 74. As will be explainedbelow, aperture 76 helps secure ligating slide 14 in the closedposition.

A resilient engagement member 78 operates to secure the ligating slide14 in the closed position. The resilient engagement member 78 isgenerally L-shaped and includes a lingually-extending prong 80 that isreceived in a recess 82 formed in support surface 46. The free end ofthe resilient engagement member 78 is provided with a labially-extendingdetent or projection 84, which corresponds generally in cross sectionwith the cross section of aperture 76 in ligating slide 14. Theprojection 84 extends into aperture 76 in ligating slide 14 whenligating slide 14 is in the closed position. The engagement between theprojection 84 and the aperture 76 holds the ligating slide 14 in theclosed position against movement that would otherwise open the slide 14.As a result, ligating slide 14 is unlikely to be unintentionally movedfrom the closed position to the opened position.

The free end of resilient engagement member 78 carrying projection 84 iselastically compressed when ligating slide 14 is in an opened positionand projection 84 engages the lingual surface of ligating slide 14.Consequently, the free end of resilient engagement member 78 is capableof resiliently flexing or deforming in the labial direction and towardligating slide 14 when the projection 84 is aligned with aperture 76,for selectively engaging the projection 84 with the aperture 76 so as tolock the ligating slide 14 in the closed position. To that end,resilient engagement member 78 is biased in the labial direction toforce projection 84 away from the tooth 23 and toward ligating slide 14.

In another advantageous aspect of the invention, it is desirable toprovide an archwire slot 16 that provides a close fit with the archwire18 being inserted therein. Thus as shown in FIGS. 3, 4A and 4B, thearchwire slot 16 typically has a generally rectangular configuration.The mutual arrangement of the base surface 40 and the side slot surfaces42, 44 is generally rectangular and provides a close fit to a generallyrectangular archwire 18. Nevertheless, because the base plane 58 of thearchwire slot 16 and the translation plane 60 along which ligating slide14 travels are angled with respect to each other, the ligating slide 14has to be modified in order to provide a close fit to the labial surfaceof archwire 18. To this end, the lingual surface of slide rails 70, 72includes a first and second portion 86, 88 respectively. First portion86 engages the slide grooves 48, 50 of slide engagement track 56. Thesecond portion 88 is angled with respect to first portion 86 such thatsecond portion 88 is generally parallel to base plane 58. Second portion88 covers the archwire slot 16 when ligating slide 14 is in the closedposition. The second portion 88 is angled by an amount substantiallyequal to the angle A between the base plane 58 and translation plane 60.In this way, ligating slide 14 provides a close fit to the labialsurface of archwire 18.

In yet another advantageous aspect of the invention, the labial portion34 of occlusal side 22 extends in the labial direction beyond thearchwire slot 16 to define a ledge, generally shown at 90, extending inthe mesial-distal direction. Ledge 90 includes a labial surface 92 thatis generally parallel to base plane 58. When the ligating slide 14 ismoved to the closed position, the occlusal end of the second portion 88on slide rails 70, 72 abuts the labial surface 92 of ledge 90 and iscovered by labial portion 34 of occlusal side 22. In this way, food orother material in the oral cavity is prevented from contacting theocclusal edge of ligating slide 14 and inadvertently dislodging slide 14to the opened position. Furthermore, labial portion 34 provides a stopso as to prevent ligating slide 14 from overshooting the closed positionas the ligating slide is being moved from the open position to theclosed position.

To regulate the movement of the ligating slide 14 relative to bracketbody 12, the bracket body 12 may include one of a projecting portion ora receiving portion, and ligating slide 14 may include the other of theprojecting portion of the receiving portion. The projecting portion andreceiving portion cooperate to regulate the movement of ligating slide14. For example, as shown in FIG. 4A, ligating slide 14 includes aretaining slot 94 (FIG. 1) through ligating slide 14 and extendinggenerally in the occlusal-gingival direction. Retaining slot 94 may beformed in the distal portion 66 of ligating slide 14, as shown in FIGS.1 and 2, but may also be formed in the mesial portion 64. A retainingpin 96 includes a lingual portion received within a recess 98 formed insupport surface 46 that aligns with the slot 94 in ligating slide 14.The retaining pin 96 projects in the labial direction and is received inslot 94 so that as the ligating slide 14 moves between opened and closedpositions, retaining slot 94 moves relative to retaining pin 96, asshown in FIG. 2. The retaining pin/slot configuration preventsaccidental or unintentional detachment of the ligating slide 14 from thebracket body 12 during use when the ligating slide 14 is positioned inthe opened position. It should be realized that the retaining pin/slotconfiguration does not lock the ligating slide 14 in any position, asdoes engagement member 78, but regulates the movement of the ligatingslide 14 in the occlusal-gingival direction.

Additionally, the length of retaining slot 94 limits theocclusal-gingival range of movement of ligating slide 14. The retainingslot 94 may be configured lengthwise so that in the fully openedposition, the archwire 18 may be inserted into archwire slot 16. Forinstance, the retaining pin 96 may abut a first slot end 100 when theocclusal edge of ligating slide 14 is approximately flush with archwireslot surface 44. In this way, the archwire 18 may be easily insertedinto the archwire slot 16. A second slot end 102 may be configured sothat the projection 84 of resilient engagement member 78 is permitted toalign with aperture 76 in ligating slide 14 so as to lock the ligatingslide 14 in the closed position. Retaining pin 96 may abut second slotend 102 when ligating slide 14 is in the closed position.

An alternate embodiment of the self-ligating orthodontic bracket 10 isshown in FIG. 4B, in which like reference numerals refer to likefeatures in FIG. 4A. In this embodiment, the receiving portion isincluded on the bracket body 12 and the projecting portion is includedon the ligating slide 14. In particular, bracket body 12 includes aretaining groove 104 in the support surface 46 extending generally inthe occlusal-gingival direction. The retaining groove 104 may be formedin support surface 46 adjacent the distal side 28 of bracket body 12,but may also be formed adjacent the mesial side 26. A retaining pin 106includes a labial portion received within a recess 108 in ligating slide14 that aligns with retaining groove 104 in bracket body 12. Theretaining pin 106 projects in the lingual direction and is received inretaining groove 104 so that as the ligating slide 14 moves betweenopened and closed positions, retaining pin 106 moves relative toretaining groove 104. In operation, the retaining pin/slot configurationshown in FIG. 4B functions in substantially the same manner as theretaining pin/slot configuration shown and described above for FIG. 4A.

In FIGS. 5A and 5B, in which like reference numerals refer to likefeatures in FIGS. 1-4A, the projecting portion and receiving portionhave an alternate configuration and/or location for regulating themovement of ligating slide 14 relative to bracket body 12. For example,in the embodiment shown in FIG. 5A, one of the guides, such as guide 52,of bracket body 12 includes an aperture 110 in the mesial side 26 whichextends therethrough. A retaining ball 112 is pressed into aperture 110with an interference fit so that a portion of retaining ball 112 extendsinto the space between guide 52 and support surface 46. The mesialsurface of rail 70 includes a retaining groove 114 (shown in phantom)extending generally in the occlusal-gingival direction and defining afirst end and second end 116, 118, respectively. The retaining ball 112projects in the distal direction and is received in retaining groove 114so that as ligating slide 14 moves between the opened and closedpositions, retaining groove 114 moves relative to retaining ball 112.Those of ordinary skill in the art will recognize that the retainingball 112 and corresponding retaining groove 114 may also be located inthe distal side 28 of bracket body 12 and ligating slide 14.

The retaining ball/groove configuration prevents accidental orunintentional detachment of the ligating slide 14 from bracket body 12during use when the ligating slide 14 is positioned in the open positionand functions in substantially the same manner as the retaining pin/slotconfiguration shown and described above for FIG. 4A. For instance, thelength of retaining groove 114 limits the occlusal-gingival range ofmovement of ligating slide 14. The retaining groove 114 is configured sothat in the fully open position, the archwire 18 may be inserted intoarchwire slot 16. The retaining ball 112 may abut first groove end 116when the occlusal end of the ligating slide 14 is approximately flushwith archwire slot surface 44. In this way, the archwire 18 may beeasily inserted into the archwire slot 16. Furthermore, the secondgroove end 118 is configured so that the projection 84 of resilientengagement member 78 may be permitted to align with aperture 76 inligating slide 14 so as to lock the ligating slide 14 in the closedposition. Retaining ball 112 may abut second groove end 118 whenligating slide 14 is in the closed position.

Although the embodiment shown in FIG. 5A shows the projecting portionassociated with the bracket body 12 and the receiving portion associatedwith the ligating slide 14, the invention is not so limited as thereceiving portion may be associated with the bracket body 12 and theprojecting portion may be associated with the ligating slide 14. In thealternate embodiment of the self-ligating orthodontic bracket 10 shownin FIG. 5B, bracket body 12 includes a retaining groove 120 in thedistal surface of guide 52 extending generally in the occlusal-gingivaldirection and defining first and second groove ends 122, 124,respectively. A retaining pin 126 includes a distal portion receivedwithin a recess 128 in ligating slide 14 that aligns with retaininggroove 120 in guide 52. The retaining pin 126 projects in the mesialdirection and is received in retaining groove 120 so that as theligating slide 14 moves between opened and closed positions, retainingpin 126 moves relative to retaining groove 120. In operation, theretaining pin/slot configuration shown in FIG. 5B functions insubstantially the same manner as the retaining ball/groove configurationshown and described above for FIG. 5A.

In these embodiments, the bracket body 12 may be made by any suitableforming technique, such as metal injection molding (MIM), from abiocompatible metal, such as a stainless steel and, more specifically, a17-4 stainless steel. The resilient engagement member 78 may be madefrom any suitable material, including stainless steels, titanium alloysand Ni/Ti type superelastic materials. The ligating slide 14 may beformed by any suitable process, such as MIM, from any biocompatiblematerial, including metals such as stainless steel.

With reference to FIG. 2, the ligating slide 14 in the closed positionblocks the entrance to the archwire slot 16 to capture the archwire 18therein and the engagement between projection 84 and aperture 76provides a latched condition. The ligating slide 14 may be unlockedusing an end of a tool (not shown) designed to press the projection 84inwardly (i.e., lingually) toward the tooth 23 with a force sufficientto overcome the bias applied by resilient member 78 and disengage theprojection 84 from the aperture 76 in the ligating slide 14 to providean unlatched condition. When the projection 84 is moved by the toolinwardly (i.e., lingually) by a distance adequate to substantially clearthe plane of the lingual surface of the ligating slide 14, the ligatingslide 14 is freely movable using a force applied by the toolocclusal-gingivally toward the opened position in a slideable manner andguided by guides 52, 54. The motion of the ligating slide 14 may bepositively stopped in the opened position by contact between theretaining pin 96 and the first slot end 100 of retaining slot 94.

To place the ligating slide 14 in the closed position, slide 14 is movedocclusal-gingivally until the projection 84 springs outwardly under thebias applied by resilient member 78 and is received in the aperture 76.The ligating slide 14 is then securely locked in the closed position.The engagement of the projection 84 into the aperture 76 may create atactile effect which is perceptible to a clinician and/or emits anaudible sound, such as a click, that is likewise perceptible by aclinician. The alternate embodiments shown in FIGS. 4B, 5A and 5B may beoperated in a similar manner.

The self-ligating bracket of the invention provides a number ofadvantages over traditional molar brackets, such as buccal tubes orconvertible buccal tubes. In particular, the self-ligating bracket maybe used in severely rotated cases without constraining the movement ofthe archwire. Traditional self-ligating brackets, however, have someproblems when applied to molar teeth. The self-ligating bracket of theinvention overcomes these limitations. In particular, self-ligatingbracket of the invention provides a slide engagement track for theligating slide that is angled so that the edge of the ligating slidedoes not contact the gingiva surrounding a molar tooth when the slide isopened. The bracket also provides a contoured-shaped surface thatprevents occlusal interference with teeth on the opposite jaw. Thebracket further provides a mechanism for regulating the movement of theligating slide so as to prevent the ligating slide from disengaging fromthe bracket body.

While the invention has been illustrated by a description of variousembodiments and while these embodiments have been described inconsiderable detail, it is not the intention of the applicant torestrict or in any way limit the scope of the appended claims to suchdetail. Additional advantages and modifications will readily appear tothose skilled in the art. For example, as shown in the figures, theself-ligating orthodontic bracket 10 may include mesial and/or distalhooks that aid in the orthodontic treatment of teeth. The invention inits broader aspects is therefore not limited to the specific details,representative apparatus and methods, and illustrative examples shownand described. Accordingly, departures may be made from such detailswithout departing from the spirit and scope of applicant's inventiveconcept.

What is claimed is:
 1. An orthodontic bracket comprising: a bracket bodythat is adapted to be secured to a tooth and that includes an archwireslot, a ledge on one side of the archwire slot, a slide engagement trackon an opposite side of the archwire slot from the ledge, and aprojection extending labially within the slide engagement track andfixed relative thereto when the bracket body is secured to a labialsurface of a tooth, a ligating slide that is movable in the slideengagement track between an opened position and a closed position andincludes a leading edge, a first slide rail, a second slide rail, and arecess between the first slide rail and the second slide rail, and abiasing member that is biased when the ligating slide is moved from theclosed position, wherein the recess is configured to receive at leastpart of the projection and the ledge is configured to receive theleading edge of the ligating slide when the ligating slide is in theclosed position, and wherein the projection and the biasing member areseparate and distinct pieces.
 2. The bracket of claim 1, wherein thebracket body includes a labial portion that defines at least a portionof the ledge and at least partially closes off the ledge from anocclusal side of the bracket body when the bracket body is secured to alabial surface of a tooth.
 3. An orthodontic bracket comprising: abracket body that is adapted to be secured to a tooth and that includesan archwire slot, a ledge on one side of the archwire slot, a slideengagement track on an opposite side of the archwire slot from theledge, and a projection extending labially within the slide engagementtrack and fixed relative thereto when the bracket body is secured to alabial surface of a tooth, a ligating slide that is movable in the slideengagement track between an opened position and a closed position andincludes a leading edge, a first slide rail, a second slide rail, and arecess between the first slide rail and the second slide rail, and abiasing member that is biased when the ligating slide is moved from theopened position, wherein the recess is configured to receive at leastpart of the projection and the ledge is configured to receive theleading edge of the ligating slide when the ligating slide is in theclosed position, and wherein the projection and the biasing member areseparate and distinct pieces.